#pragma once
#include "requestor.hpp"

namespace Json_rpc
{
    namespace client
    {
        class Provider
        {
        public:
            using ptr = std::shared_ptr<Provider>;
            Provider(const Requestor::ptr requestor) : _requestor(requestor) {}
            bool registryMethod(const BaseConnection::ptr &conn, const std::string &method, const Address &host)
            {
                auto req_msg = MessageFactory::create<ServiceRequest>();
                req_msg->setId(UuidUtil::uuid());
                req_msg->setMType(MType::REQ_SERVICE);
                req_msg->setMethod(method);
                req_msg->setOptype(ServiceOptype::SERVICE_REGISTRY);
                req_msg->setHost(host);
                BaseMessage::ptr msg_rsp;
                bool ret = _requestor->send(conn, req_msg, msg_rsp);
                if (ret == false)
                {
                    ELOG("%s 服务注册失败", method.c_str());
                    return false;
                }
                auto service_rsp = std::dynamic_pointer_cast<ServiceResponse>(msg_rsp);
                if (service_rsp.get() == nullptr)
                {
                    ELOG("响应类型转换失败！");
                    return false;
                }
                if (service_rsp->rCode() != RCode::RCODE_OK)
                {
                    ELOG("服务注册失败: %s", errReason(service_rsp->rCode()).c_str());
                    return false;
                }
                return true;
            }

        private:
            Requestor::ptr _requestor;
        };

        class MethodHost
        {
        public:
            using ptr = std::shared_ptr<MethodHost>;
            MethodHost(const std::vector<Address> &hosts) : _hosts(hosts.begin(), hosts.end()), _idx(0) {}
            void appendHost(const Address &host)
            {
                // 收到了服务上线请求后被调用
                std::unique_lock<std::mutex> lock(_mutex);
                _hosts.emplace_back(host);
            }
            void removeHost(const Address &host)
            {
                // 收到了服务下线请求后被调用
                std::unique_lock<std::mutex> lock(_mutex);
                for (auto it = _hosts.begin(); it != _hosts.end(); it++)
                {
                    if (*it == host)
                    {
                        _hosts.erase(it);
                        break;
                    }
                }
            }
            Address chooseHost()
            {
                std::unique_lock<std::mutex> lock(_mutex);
                size_t pos = _idx++ % _hosts.size();
                return _hosts[pos];
            }
            bool empty()
            {
                return _hosts.empty();
            }

        private:
            std::mutex _mutex;
            size_t _idx;
            std::vector<Address> _hosts;
        };

        class Discoverer
        {
        public:
            using OfflineCallback = std::function<void(const Address &)>;
            using ptr = std::shared_ptr<Discoverer>;
            Discoverer(const Requestor::ptr &requestor,const OfflineCallback &cb) : _requestor(requestor),_offline_callback(cb) {}
            bool serviceDiscoverery(const BaseConnection::ptr &conn, const std::string &method, Address &host)
            {
                {
                    // 保存过提供者信息直接返回地址
                    std::unique_lock<std::mutex> lock(_mutex);
                    auto it = _method_hosts.find(method);
                    if (it != _method_hosts.end())
                    {
                        if (it->second->empty() == false)
                        {
                            host = it->second->chooseHost();
                            return true;
                        }
                    }
                }
                // 向服务端进行服务发现
                auto req_msg = MessageFactory::create<ServiceRequest>();
                req_msg->setId(UuidUtil::uuid());
                req_msg->setMType(MType::REQ_SERVICE);
                req_msg->setMethod(method);
                req_msg->setOptype(ServiceOptype::SERVICE_DISCOVERY);
                BaseMessage::ptr rsp_msg;
                bool ret = _requestor->send(conn, req_msg, rsp_msg);
                if (ret == false)
                {
                    ELOG("服务发现失败！");
                    return false;
                }
                auto service_rsp = std::dynamic_pointer_cast<ServiceResponse>(rsp_msg);
                if (!service_rsp)
                {
                    ELOG("响应类型转换失败!");
                    return false;
                }
                if (service_rsp->rCode() != RCode::RCODE_OK)
                {
                    ELOG("服务发现失败 %s", errReason(service_rsp->rCode()).c_str());
                    return false;
                }
                std::unique_lock<std::mutex> lock(_mutex);
                auto method_host = std::make_shared<MethodHost>(service_rsp->hosts());
                if (method_host->empty())
                {
                    ELOG("%s 服务发现失败 没有能够提供服务的主机！", method.c_str());
                    return false;
                }
                host = method_host->chooseHost();
                _method_hosts[method] = method_host;
                return true;
            }
            // 提供给dispatcher模块进行服务上线下线通知的回调函数
            void onServiceRequest(const BaseConnection::ptr &conn, const ServiceRequest::ptr &msg)
            {
                // 1. 判断是上线还是下线请求，如果都不是那就不⽤处理了
                auto optype = msg->optype();
                std::string method = msg->method();
                std::unique_lock<std::mutex> lock(_mutex);
                if (optype == ServiceOptype::SERVICE_ONLINE)
                {
                    // 2. 上线请求：找到MethodHost，向其中新增⼀个主机地址
                    auto it = _method_hosts.find(method);
                    if (it == _method_hosts.end())
                    {
                        //没找到
                        auto method_host = std::make_shared<MethodHost>(std::vector<Address>());
                        method_host->appendHost(msg->host());
                        _method_hosts[method] = method_host;
                    }
                    else
                    {
                        //找到了
                        it->second->appendHost(msg->host());
                    }
                }
                else if (optype == ServiceOptype::SERVICE_OFFLINE)
                {
                    // 3. 下线请求：找到MethodHost，从其中删除⼀个主机地址
                    auto it = _method_hosts.find(method);
                    if (it == _method_hosts.end())
                    {
                        return;
                    }
                    it->second->removeHost(msg->host());
                    _offline_callback(msg->host());
                }
            }

        private:
            OfflineCallback _offline_callback;
            std::mutex _mutex;
            std::unordered_map<std::string, MethodHost::ptr> _method_hosts;
            Requestor::ptr _requestor;
        };
    }
}